I downloaded dotLRN from CVS and tried installing on PostgreSQL 7.1.3.
After successfully installing the OpenACS packages, I got an error when I tried to install the dotlrn package. I ran the scripts in dotlrn-create.sql one by one, until I got to this error from security-create.sql:
psql:security-create.sql:82: ERROR: triggered data change violation on relation "acs_privilege_hierarchy_index"
I ran the commands one by one in psql, and all went well. The other dotLRN packages installed smoothly after that, and I'm now in dotLRN Exploration Heaven.